"Today the Wenzhou Sanjiang church is being demolished; where will our more than 1,000 believers gather after this? Why tear down our church?" Caoyuan Zhibing said in a microblog post that included a photo said to be from the scene, in the eastern province of Zhejiang.

Thousands of worshippers have previously flocked to the church to protect it, but online posts said police locked down the area on Monday, blocking traffic. "The church of God is being demolished, how do you feel? So sad," said a poster using the name Joyful Hope.

The government of Yongjia county, which administers the area, declined to comment. "We are unclear about these issues," said an official at the county's main office.

A US-based religious rights group, the China Aid Association (CAA), said last week that the local government had reneged on a deal under which the church would demolish just two storeys of an accessory building, not the main structure.

CAA said several churches in Wenzhou, a centre for private enterprise that is also home to a thriving Christian community, have been forced to remove prominent crosses from their rooftops and threatened with partial or total demolition.

The state-linked China Christian Council estimates the country has around 20 million Christians – not including Catholics – 70% of whom live in rural areas.

But the true number of worshippers could be higher, as so-called underground or house churches have also sprung up among Christians seeking to practise their faith outside government control.